Wafers are fabricated with a plurality of dies (sometimes as many as hundreds) on each wafer. Each of the dies on a wafer subsequently forms an integrated circuit chip or magnetic transducer head. The dies are tested while on the wafer to determine if they have been produced properly. The defective dies are marked to distinguish them from the satisfactory dies. The dies are then cut from the wafer and the satisfactory dies are retained for use as integrated circuit chips.
When the dies on the wafers are intended to form integrated circuit chips, the wafers are produced from a plurality of successive layers, some of electrically conductive material and others of electrically insulating material. Each of these layers has an individual pattern. When a layer of an electrically conductive material is formed, it generally is produced in a pattern to represent electrical circuitry. To produce this electrical circuitry, a layer of an electrically conductive material is initially deposited on the wafer, hopefully in a substantially uniform thickness. The layer may then be masked with a material which is subjected to light in a pattern corresponding to the pattern of the electrical circuitry to be produced. The masking material subjected to the light is impervious to an etching material such as an acid.
The remaining portions of the layer may then be etched as by an acid. The masking material subjected to the light may then be removed from the remaining electrically conductive material in the layer. The electrically conductive material remaining in such layer, and the electrically conductive material in a plurality of other layers produced in the same manner, define the electrical circuitry for each die on the wafer.
Substrates may also be fabricated to provide dies which are then coated with a magnetizable material to be used in magnetic heads. The magnetic head is then disposed in contiguous relationship to a memory member such as a magnetizable disc. A transducing action is then provided between the magnetic head and the magnetizable disc to transfer information, generally binary, between the die on the magnetic head and the magnetizable disc.
The die for magnetic heads are generally made from an insulating material or are coated with an insulating material before subsequent layers are deposited on the insulating material. For example, the dies for integrated circuit chips are made from silicon dioxide. The dies for magnetic heads are generally coated with a layer of aluminum oxide. The insulating material or the insulating layer sometimes have artifacts in the layer. For example, hydrocarbons sometimes occur on the surface of the insulating material or the insulating layer. Such hydrocarbons prevent subsequent layers of material from being deposited uniformly on the insulating material in part from the fact that the depositions do not fully adhere to the hydrocarbons. The problem discussed in this paragraph has existed for some time.